HUAWEI OceanStor 5300&5500&5600&5800 V3 Converged Storage … · · 2015-01-2815 Acronyms and Abbreviations..... 38. HUAWEI OceanStor 5300&5500&5600&5800 V3 Converged Storage Systems

HUAWEI OceanStor 5300&5500&5600&5800 V3 Converged Storage Systems

Technical White Paper

Issue 2.0

Date 2014-12

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2014. All rights reserved.

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Huawei Technologies Co., Ltd.

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HUAWEI OceanStor 5300&5500&5600&5800 V3

Converged Storage Systems

Technical White Paper Contents

Contents

1 Overview ................................................................................................................................... 1

2 Definition of "On-Demand, Simple & Efficient, Secure & Reliable" ............................... 3

3 Storage Architecture................................................................................................................. 5

4 SmartVirtualization ................................................................................................................. 8

5 SAN and NAS Converged Architecture .............................................................................. 10

6 SmartMigration ...................................................................................................................... 12

7 High-Density Disk Enclosure ............................................................................................... 14

8 SmartDedupe and SmartCompression ................................................................................ 23

9 SmartTier ................................................................................................................................. 25

10 SmartThin.............................................................................................................................. 28

11 SmartQoS .............................................................................................................................. 31

12 SmartPartition ....................................................................................................................... 34

13 DeviceManager ..................................................................................................................... 36

14 Summary ............................................................................................................................... 37

15 Acronyms and Abbreviations ............................................................................................. 38



Technical White Paper 1 Overview

1 Overview

Evolving from mainframe servers to midrange computers, PCs, and desktop Internet, the

information technology (IT) is penetrating into all walks of life. Nowadays, we are embracing

the mobile Internet era. The change of application environments hastens data explosion.

According to Gartner's statistics, about 2.6 EB of data was generated around the world in the

era of midrange computers and 15.8 EB of data when PCs were popular. In the era of desktop

Internet, the amount of data was almost quadrupled, reaching 54.5 EB. Up to 1800 EB of data

may be generated in the era of mobile Internet. The skyrocketing amount of data not only

requires superlarge storage capacities but also imposes demanding requirements on other

features of storage products.

Since data sources are increasingly diversified, clouds will gradually become the largest data

sources, replacing PCs and consumer electronics (CE). The following figure shows predicted

rankings of data sources.

Figure 1-1 Predicted rankings of data sources

Since data sources are changing constantly, data types change accordingly. Although the

amount of critical service data, such as databases, increases continuously, it accounts for a decreasing percentage of the total data amount; whereas enterprise office data, such as emails

0

500

1000

1500

2000

2500

3000

3500

4000 Smartphone/Feature phone

Tablet computer

Cloud SSD

Cloud

Consumer electronics storage

Client SSD

Client PC



Technical White Paper 1 Overview

and large media files, once accounted for the highest percentage of the total data amount. In

recent years, since the amount of personal data increases sharply, media and entertainment

data replaces enterprise office data as the largest data sources. In 1993, critical service data

and enterprise office data accounted for 50% of the total data amount respectively, and the

amount of personal data could be ignored. In 2002, 70% of data was enterprise office data,

and 20% was critical service data. Since 2010, personal data accounts for 50% of the total

data volume, whereas enterprise office data accounts for 40%, and critical service data

accounts for only 10%.

Different types of data from diversified sources have different requirements on the

performance, reliability, and costs of storage media. Critical service data requires

high-performance and robust-reliability storage devices, whereas personal entertainment data

requires inexpensive storage devices. The reality is that critical service data and personal

entertainment data usually need to be stored in a single set of storage device. Such

contradicting requirements impose new challenges. To keep with IT development,

next-generation mid-range storage products must have:

Integrated, simple, intelligent, and cost-effective system architecture

High flexibility, meeting diverse storage needs

Agile data planning and management

Rich and practical functions




2 Definition of "On-Demand, Simple & Efficient, Secure &

Reliable"

2 Definition of "On-Demand, Simple & Efficient, Secure & Reliable"

HUAWEI OceanStor V3 converged storage systems (the V3 converged storage systems for

short) are brand-new storage systems designed for enterprise-class applications. Leveraging a

storage operating system built on a cloud-oriented architecture, a powerful new hardware

platform, and suites of intelligent management software, the V3 converged storage systems

deliver industry-leading functions, performance, efficiency, reliability, and ease-of-use. They

provide data storage for applications such as large-database Online Transaction Processing

(OLTP)/Online Analytical Processing (OLAP), file sharing, and cloud computing, and can be

widely applied to industries ranging from government, finance, telecommunication, to energy,

and media assets. Meanwhile, the V3 converged storage systems can provide a wide range of

efficient and flexible backup and disaster recovery solutions to ensure business continuity and

data security, delivering excellent storage services.

On-demand: providing customers with on-demand storage services

Thanks to SmartVirtualization, the V3 converged storage systems can efficiently manage

storage systems from other mainstream vendors and unify resource pools for central and flexible resource allocation.

SmartMigration migrates host services from a source LUN to a target LUN without

interrupting these services and then enables the target LUN to take over services from

the source LUN without being noticed by the hosts. After the service migration is

complete, all service-related data has been replicated from the source LUN to the target

LUN.

SAN and NAS are converged on one platform that provides file and block access services, enabling flexible configurations and meeting diverse application requirements.

Simple & efficient: simplifying management and improving efficiency

High-density disk enclosures fully utilize their 4 U space. Vertical instead of horizontal

disk slots are provided, and the size of cascading boards is reduced by more than half,

providing as much space as possible for disks. The delicate air duct design, optimized

fan speed adjustment policy, and enhanced fan usage resolve the heat dissipation issue and meet the noise and power consumption requirements.




2 Definition of "On-Demand, Simple & Efficient, Secure &

Reliable"

SmartTier automatically analyzes data access frequencies per unit time and migrates data

to disks of different performance levels based on the analysis result. (High-performance

disks store most frequently accessed data, performance disks store less frequently

accessed data, and large-capacity disks store seldom accessed data.) In this way, the

optimal overall performance is achieved, and the IOPS cost is reduced.

SmartThin allocates storage space on demand rather than pre-allocating all storage space

at the initial stage. It is more cost-effective because customers can start business with a

few disks and add disks based on site requirements. In this way, the initial purchase cost

and total cost of ownership (TCO) are reduced.

SmartDedupe and SmartCompression deduplicate and compress data before data storage,

reducing storage space for data storage, lowering the storage cost per GB, and improving the data storage efficiency.

Secure & reliable: establishing reliable resource pools based on a virtualization architecture

SmartQoS categorizes service data based on data characteristics (each category

represents a type of application) and sets a priority and performance objective for each

category. In this way, resources are allocated to services properly, fully utilizing system resources.

The core idea of SmartPartition is to ensure the performance of mission-critical

applications by partitioning core system resources. Users can configure cache partitions

of different sizes. The V3 converged storage systems ensure the number of cache

partitions occupied by service applications. Based on the actual service condition, the V3

converged storage systems dynamically adjust the number of concurrent access requests

from hosts to different cache partitions, ensuring the service application performance of each partition.



Technical White Paper 3 Storage Architecture

3 Storage Architecture

The V3 converged storage systems employ an inter-engine IP interconnection architecture to

achieve scale-out. Inter-engine service switching and mirroring channels employ 10GE. One

V3 storage system supports a maximum of four engines, each providing two controllers. In

other words, one V3 storage system supports a maximum of eight controllers. Each controller

is connected to two switching planes using 10GE switches for data forwarding.

The two controllers in an engine are interconnected based on PCIe 3.0. That is, 8-lane PCIe

3.0 forms high-speed mirroring channels between the two controllers, as shown in the

following figure.

Figure 3-1 Two controllers in an engine interconnected based on PCIe 3.0

Switching channels support direct-connection networks and switch-connection networks. On

a switch-connection network as shown in Figure 3-2, multiple controller enclosures are

connected to two data switches over 10GE to exchange data. Such a cluster supports a

maximum of eight controllers. On a direct-connection network as shown in Figure 3-3, two

network ports of one network adapter are connected to the controllers in another engine. Such

a cluster supports a maximum of four controllers. Dual switching links are used to ensure the

redundancy of cluster data exchange networks. IP interconnection reserves sufficient space for

future cluster expansion, improving cluster scalability. Data exchange between controllers and

mirroring channels employ the all-PCIe interconnection architecture, accelerating data

exchange.




Figure 3-2 Switch-connection network employing a multi-controller architecture

Figure 3-3 Direct-connection network employing a four-controller architecture




Four controller enclosures are connected to two data switches over 10GE to exchange data,

ensuring the redundancy of cluster data exchange networks. IP interconnection reserves

sufficient space for future cluster expansion, improving cluster scalability. Data exchange

between controllers and mirroring channels employ the all-PCIe interconnection architecture,

accelerating data exchange.

The V3 converged storage systems boast all-PCIe 3.0 interconnection, back-end SAS 3.0, and

high-speed channels and powerful computing capability of Intel Ivy Bridge CPUs, meeting

increasingly demanding performance requirements. In addition, the V3 converged storage

systems employ the single point of failure prevention design and scale-out to deliver high

reliability and flexible scalability under a tight budget.



Technical White Paper 4 SmartVirtualization

4 SmartVirtualization

The V3 converged storage systems aim at providing rich virtualization functions for

heterogeneous storage systems of customers:

The heterogeneous takeover function reduces complexity in managing heterogeneous storage systems and improves LUN performance.

The heterogeneous online migration function allows data to be smoothly migrated among LUNs of heterogeneous storage systems without interrupting services.

The heterogeneous remote replication function implements disaster recovery for LUNs

of heterogeneous storage systems.

The heterogeneous snapshot function implements rapid backup for LUNs of

heterogeneous storage systems. The heterogeneous virtualization feature provided by the V3 converged storage systems is called SmartVirtualization.

SmartVirtualization uses LUNs mapped from heterogeneous storage systems to the local

storage system as logical disks (LDs) that can provide storage space for the local storage

system and create eDevLUNs that can be mapped to the host on LDs. LDs provide data

storage space for data volumes, and the local storage system provides storage space for meta

volumes of eDevLUNs. SmartVirtualization ensures the data integrity of external LUNs.

Figure 4-1 SmartVirtualization



Technical White Paper 4 SmartVirtualization

eDevLUNs and local LUNs have the same properties. For this reason, SmartMigration,

HyperReplication/S, HyperReplication/A, and HyperSnap are used to provide online

migration, synchronous remote replication, asynchronous remote replication, and snapshot

functions respectively for LUNs of heterogeneous storage systems. Meanwhile, SmartQoS,

SmartPartition, and cache write back are used to improve the LUN performance of

heterogeneous storage systems.

SmartVirtualization applies to:

Heterogeneous array takeover

As users' data centers develop, storage systems in the data centers may come from

different vendors. How to efficiently manage and apply storage systems from different

vendors is a challenge that storage administrators must tackle. Storage administrators can

leverage the takeover function of SmartVirtualization to simplify heterogeneous array

management. They need only to manage Huawei storage systems, and their workloads

are remarkably reduced. In such a scenario, SmartVirtualization simplifies system management.

Heterogeneous data migration

A large number of heterogeneous storage systems whose warranty periods are about to

expire or whose performance cannot meet service requirements may exist in a customer's

data center. After purchasing the V3 converged storage systems, the customer wants to

migrate services from the existing storage systems to the new storage systems. The

customer can leverage the online migration function of SmartMigration to migrate data

on LUNs of heterogeneous storage systems to the new storage systems. The migration

process has no adverse impact on ongoing host services, but the LUNs must be taken

over before the migration. In such a scenario, SmartVirtualization ensures ongoing host services when data on LUNs of heterogeneous storage systems is migrated.

Heterogeneous disaster recovery

If service data is scattered at different sites and there are demanding requirements for

service continuity, the service sites need to serve as backup sites mutually, and service

switchovers can be performed between sites. When a disaster occurs, a functional service

site takes over services from the failed service site and recovers data. However, as

storage systems at the data site come from different vendors, data on the storage systems

cannot be backed up mutually. The synchronous and asynchronous replication functions

of SmartVirtualization enable data on LUNs of heterogeneous storage systems to be

backed up mutually, achieving data disaster recovery among sites.

Heterogeneous data protection

Data on LUNs of heterogeneous storage systems may be attacked by viruses or damaged.

SmartVirtualization leverages the heterogeneous snapshot function to create snapshots

for LUNs of heterogeneous storage systems instantly, and rapidly restores data at a specific point in time using the snapshots if data is damaged.



Technical White Paper 5 SAN and NAS Converged Architecture

5 SAN and NAS Converged Architecture

Figure 5-1 shows the converged architecture of the V3 storage system. On this architecture,

file systems and LUNs work above the space subsystem, whereas the storage pool subsystem

based on RAID 2.0+ works under the space subsystem. File systems and LUNs directly

interact with the space subsystem. The file system architecture is based on objects. Each file

or directory serves as an object, and each file system is a collection of objects. Generally,

LUNs are divided into thin LUNs and thick LUNs. Both the thin LUNs and thick LUNs are

from the storage pool system and space system instead of file systems. In this way, this

converged architecture delivers a simplified software stack and provides a higher storage

efficiency than the traditional unified storage architecture, as shown in Figure 5-2. In addition,

LUNs and file systems are independent from each other.

Figure 5-1 OceanStor OS architecture

Figure 5-2 Traditional unified storage architecture



Technical White Paper 5 SAN and NAS Converged Architecture

For the NAS function of EMC VNX, X-Blade (a NAS gateway) is required to provide file

sharing services. File systems and block services work on different operation platforms,

complicating the architecture and software stack. For NetApp FAS series, although the unified

storage system works on a unified architecture, the block semantics is based on Write

Anywhere File Layout (WAFL), and its software layer is more complex than the V3

converged storage systems. The V3 converged storage systems built on a converged

architecture are more efficient than other storage systems in terms of software stack.



Technical White Paper 6 SmartMigration

6 SmartMigration

The V3 converged storage systems employ LUN migration to provide intelligent data

migration. Services on a source LUN can be completely migrated to the target LUN without

interrupting ongoing services. In addition to service migration within a storage system, LUN

migration also supports service migration between a Huawei storage system and a compatible

heterogeneous storage system. The LUN migration feature provided by the V3 converged

storage systems is called SmartMigration.

SmartMigration replicates all data from a source LUN to a target LUN and uses the target

LUN to completely replace the source LUN after the replication is complete. Specifically, all

internal operations and requests from external interfaces are transferred from the source LUN

to the target LUN transparently.

Implementation of SmartMigration has two stages:

1. Service data synchronization

Ensures that data is consistent between the source LUN and target LUN after service

migration.

2. LUN information exchange

Enables the target LUN to inherit the WWN of the source LUN without affecting host services.

SmartMigration applies to:

Storage system upgrade by working with SmartVirtualization

SmartMigration works with SmartVirtualization to migrate data from legacy storage

systems (storage systems from Huawei or other vendors) to new Huawei storage systems

to improve service performance and data reliability.

Service performance adjustment

SmartMigration can be used to improve or reduce service performance. It can migrate

services either between two LUNs that have different performances within a storage system or between two storage systems that have different configurations.

− Service migration within a storage system

When the performance of a LUN that is carrying services is unsatisfactory, you can

migrate the services to another LUN that provides higher performance to boost

service performance. For example, if a user requires quick read/write capabilities, the

user can migrate services from a LUN created on low-speed storage media to a LUN

created on high-speed storage media. Conversely, if the priority of a type of services

decreases, you can migrate the services to a low-performance LUN to release the



Technical White Paper 6 SmartMigration

high-performance LUN resources for other high-priority services to improve storage

system serviceability.

− Service migration between storage systems

When the performance of an existing storage system fails to meet service

requirements, you can migrate services to a storage system that provides higher

performance. Conversely, if services on an existing storage system do not need high

storage performance, you can migrate those services to a low-performance storage

system. For example, cold data can be migrated to entry-level storage systems without interrupting host services to reduce operating expense (OPEX).

Service reliability adjustment

SmartMigration can be used to adjust service reliability of a storage system.

− To enhance the reliability of services on a LUN with a low-reliability RAID level,

you can migrate the services to a LUN with a high-reliability RAID level. If services

do not need high reliability, you can migrate them to a low-reliability LUN.

− Storage media offer different reliabilities even when configured with the same RAID

level. For example, when the same RAID level is configured, SAS disks provide

higher reliability than NL-SAS disks and are more often used to carry important

services.

SmartMigration enables:

- LUN type adjustment to meet changing service requirements

- Flexible conversion between thin LUNs and thick LUNs without interrupting host services



Technical White Paper 7 High-Density Disk Enclosure

7 High-Density Disk Enclosure

High-density disk enclosures of the V3 converged storage systems employ a dual-channel

architecture for redundancy. Each of the two cascading boards provides four 6 Gbit/s mini

SAS HD ports (four PHY per port). A channel can provide 4 GB/s bandwidth. A high-density

disk enclosure can be cascaded to other disk enclosures.

Figure 7-1 Topology of a high-density disk enclosure of the V3 converged storage systems




Figure 7-2 Panel of a cascading board

The following figures show the networking diagram of a high-density disk enclosure of the

V3 converged storage systems from different views.

Figure 7-3 Top view of the network




Figure 7-4 Front and rear views of the network

At least one 6 or 12 Gbit/s SAS card must be configured for each channel of a controller.

A 6 Gbit/s SAS card provides two mini SAS ports. Mini SAS to mini SAS HD cables must be

used to connect high-density disk enclosures. The two ports are horizontally connected to

ports HOST 1 and HOST 2 of a high-density disk enclosure, and ports HOST 3 and HOST 4

serve as EXP ports and are connected to another high-density disk enclosure.

A 12 Gbit/s SAS card provides four 12 Gbit/s mini SAS HD ports. Mini SAS HD cables must

be used to connect to high-density disk enclosures. The four ports are divided into two

channels: ports 0 and 1, ports 2 and 3. Ports 0 and 1 are horizontally connected to ports HOST

1 and HOST 2 of a high-density disk enclosure, and ports HOST 3 and HOST 4 serve as EXP

ports and are horizontally connected to another high-density disk enclosure.

High-density architecture

High-density disk enclosures fully utilize their 4 U space. Vertical instead of horizontal

disk slots are provided, and the size of cascading boards is reduced by more than half. In this way, more space is provided to disks.

Figure 7-5 Disk layout in a high-density disk enclosure




Heat dissipation

Higher density requires a more powerful heat dissipation capability. Heat generated by

75 disks must be dissipated in a timely manner. Otherwise, the storage device is overheated and damaged.

The delicate air duct design, optimized fan speed adjustment policy, and enhanced fan

usage resolve the heat dissipation issue and meet the noise and power consumption

requirements.

Figure 7-6 Heat dissipation

Weight

Another challenge that high-density disk enclosures must tackle is weight. Higher

density means a heavier disk enclosure. Therefore, the cabinet cannot be fully configured. Recommend cabinet configurations are as follows:

Figure 7-7 Recommended configurations of high-density disk enclosures




The following table lists recommended configurations of high-density disk enclosures.

Table 7-1 Recommended configurations of high-density disk enclosures

Item Value

Rack 1 weight 471.8 kg

Rack 2 weight 426.8 kg

Rack 1 power consumption 5.65 kW

Rack 2 power consumption 4.8 kW

Ground load bearing capacity Single unit: 1169.4 kg per square meter

Average: 612.5 kg per square meter

You can adjust the configurations based on site requirements.

Specifications

The following table lists the specifications of high-density disk enclosures of Huawei OceanStor series storage systems.




Table 7-2 High-density disk enclosure specifications

Item Description

Host interface Mini SAS HD (four 6 Gbit/s per I/O module)

Disk interface NL-SAS

6 Gbit/s or 3 Gbit/s

Up to 75 disks per enclosure

Redundant components Power module

Cooling module

I/O module

Disk module

Chassis dimensions Height:176.5 mm (4 U)

Width: 446 mm

Depth: 790 mm (without cable management assembly)

1070 mm (with cable management assembly)

Maximum chassis weight 46.7 kg without disks

106.7 kg with disks (4 TB NL-SAS)

Total power Maximum: 1200 W

Input voltage 90 V to 264 V

Input frequency 45 to 65 Hz (typical 50 Hz or 60 Hz)

Input current 10 A

Maximum average output

power

800 W or 1200 W:

110/220 V input: four 800 W for a chassis

220 V input: two 1200 W for a chassis

Disk density

The storage density of high-density enclosures is three times that of traditional disk enclosures.




Performance

The performance per U of high-density disk enclosures is two times that of traditional disk enclosures.

As the SAS channel width of high-density disk enclosures is limited, you are advised to

ensure that the layers of cascaded high-density disk enclosures do not exceed four to ensure storage performance.




OPEX

The OPEX per disk of high-density disk enclosures is 20% lower than that of traditional

disk enclosures.

Power consumption

The power consumption per disk of high-density disk enclosures is 50% lower than that of traditional disk enclosures.




Competitor comparison

Figure 7-8 Specifications comparison



Technical White Paper 8 SmartDedupe and SmartCompression

8 SmartDedupe and SmartCompression

The V3 converged storage systems not only deliver the SAN and NAS converged architecture,

but also provide SmartDedupe and SmartCompression to shrink data for file systems and

LUNs. As one of the data storage efficiency improvement methods, SmartDedupe and

SmartCompression have extended themselves from the backup area to the primary storage

area. They play a critical role in tiered storage with the SSD tier and all-flash arrays because

they can save storage space and reduce the TCO of enterprise IT architectures.

The V3 converged storage systems implement SmartDedupe based on file systems and thin

LUNs online. In the storage systems, the data deduplication granularity is consistent with the

minimum data read and write unit (grain) of file systems or thin LUNs.

Meanwhile, as users can specify the grain size (4 KB to 64 KB) when creating file systems or

thin LUNs, the V3 converged storage systems can implement SmartDedupe based on different

granularities. When SmartDedupe is enabled, user data is delivered to the deduplication

module in grains. The deduplication module first calculates data fingerprints and then checks

whether duplicate fingerprints exist. If yes, the data block is a duplicate one and will not be

saved. If no, the data block is a new one and will be delivered to disks for storage. In addition,

byte-by-byte comparison can be enabled or disabled. If byte-by-byte comparison is enabled,

the deduplication module compares the data with the fingerprint byte by byte.

The V3 converged storage systems implement SmartCompression based on file systems and

thin LUNs online. When SmartCompression is enabled, user data is delivered to the

compression module in grains and is stored after being compressed. The compression module

combines multiple data blocks that belong to the same compression object type and have

continuous logical block addresses (LBAs) and compresses these data blocks at a time to

improve compression performance. Tests show that compression performance is the best

when the compression granularity is 32 KB. For this reason, data blocks whose size is smaller

than 32 KB are compressed together, whereas data blocks whose size is larger than 32 KB are

compressed directly.

To reduce the impact of decompression on host read performance in low-compression ratio

scenarios, the compression module checks whether the compression ratio reaches the preset

threshold. If the compression ratio does not reach the threshold, the data is considered

low-compression ratio data and will be stored as decompressed data. In this way, the data can

be read without decompression, reducing the impact on read performance.

After SmartDedupe and SmartCompression are enabled simultaneously, data is deduplicated

and then compressed before being stored onto disks. The following describes the process for

processing a data write request when SmartDedupe and SmartCompression are enabled

simultaneously:

Calculates the data fingerprint using the SHA1 algorithm.



Technical White Paper 8 SmartDedupe and SmartCompression

Checks whether a duplicate fingerprint exists in the fingerprint library of the file system

or thin LUN.

(Optional) Compares the data with the fingerprint byte by byte if byte-by-byte compression is enabled.

Returns duplicate information if a duplicate data block exists and indicates that the data block is unique if no duplicate data block exists.

Compresses the unique data block.

Writes the compressed data block to the disk and updates data block information in the

fingerprint.

Returns data block deduplication and compression information, such as deduplication

and compression flags and physical address, to the file system or thin LUN.

The following describes the process for processing a data read request when SmartDedupe

and SmartCompression are enabled simultaneously:

Reads data from the disk based on the deduplication and compression information, such

as physical address, delivered by the file system or thin LUN.

Determines whether the data block is compressed based on the deduplication and

compression flags delivered by the file system or thin LUN and directly returns the data block to the upper-layer application if the data block is not compressed.

Decompresses and returns the data block to the upper-layer application if the data block

is compressed.

In the meantime, the V3 converged storage systems provide hardware acceleration cards for

deduplication and compression. Customers can configure hardware acceleration cards based

on service requirements. Hardware acceleration cards carry operations, such as fingerprint

calculation, compression, and decompression, reducing CPU resource consumption.

SmartDedupe and SmartCompression can work with SmartCache to employ SSDs to

accelerate deduplication metadata, improving metadata query efficiency and index speed and

significantly reducing the impact of data deduplication on system performance.

Thanks to the SAN and NAS converged architecture, SmartDedupe and SmartCompression

can be enabled or disabled for file systems and thin LUNs, achieving block-based online data

shrinking. As SmartDedupe and SmartCompression are independent from each other, they can

be enabled or disabled independently. In addition, enabling and disabling these functions do

not compromise system performance. SmartDedupe and SmartCompression provided by the

V3 converged storage systems work in in-line mode. When the functions are enabled, new

data is deduplicated and compressed. When the functions are disabled, deduplicated data

cannot be restored.



Technical White Paper 9 SmartTier

9 SmartTier

The V3 converged storage systems support Huawei's self-developed SmartTier feature. This

feature is used to implement automatic storage tiering. SmartTier stores right data onto right

media at right time. SmartTier improves storage system performance and reduces storage

costs to meet enterprises' requirements on both performance and capacities. By preventing

historical data from occupying expensive storage media, SmartTier ensures effective

investment and eliminates energy consumption caused by useless capacities, reducing TCO

and optimizing cost-effectiveness.

SmartTier performs intelligent data storage based on LUNs and identifies LUNs based on a

data migration granularity from 512 KB to 64 MB. The data migration granularity is called

extent. SmartTier collects statistics on and analyzes the activity levels of data based on extents

and matches data of various activity levels with storage media. Data that is more active will

be promoted to higher-performance storage media (such as SSDs), whereas data that is less

active will be demoted to more cost-effective storage media with larger capacities (such as

NL-SAS disks). The data migration process of SmartTier consists of performance statistics

collection, performance analysis, and data migration, as shown in the following figure:

Figure 9-1 Three phases in data processing by SmartTier




Performance statistics collection and performance analysis are automated by the storage

system based on users' configuration, and data migration is initiated manually or by a

user-defined scheduled policy.

The I/O monitoring module collects performance statistics.

SmartTier allows user-defined I/O monitoring periods. During the scheduled periods, it

collects statistics on data reads and writes. Activity levels of data change throughout the data

life cycle. By comparing the activity level of one data block with that of another, the storage

system determines which data block is more frequently accessed or less frequently accessed.

The activity level of each extent is obtained based on the performance indicator statistics of

data blocks.

The working principle is as follows:

During scheduled I/O monitoring periods, each I/O is recorded to serve as data sources

for performance analysis and forecasting. The following information is recorded based

on extents: data access frequency, I/O size, and I/O sequence.

The I/O monitoring module records the I/Os of each extent based on memories. Each controller can monitor a maximum of 512 TB storage space.

The I/O monitoring module performs weighting for I/O statistics on a daily basis to weaken the impact of historical services on current services.

The data placement analysis module implements performance analysis.

The collected performance statistics are analyzed. This analysis produces rankings of extents

within the storage pool. The ranking progresses from the most frequently accessed extents to

the least frequently accessed extents in the same storage pool. Note that only extents in the

same storage pool are ranked. Then a data migration solution is created. Before data migration,

SmartTier determines the direction of relocating extents according to the latest data migration

solution.


The data placement analysis module determines the I/O thresholds of extents on each tier

based on the performance statistics of each extent, the capacity of each tier, and the

access frequency of each data block. The hottest data blocks are stored to the tier of the highest performance.

Extents that exceed the thresholds are ranked. The hottest extents are migrated first.

During data placement, a policy is made specifically for SSDs and another policy is

made to proactively migrate sequence-degraded extents from SSDs to HDDs.

The data relocation module migrates data.

Frequently accessed data (hotspot data) and seldom accessed data (cold data) are redistributed

after data migration. Random hotspot data is migrated to the high-performance tier and

performance tier, and non-hotspot data and high-sequence data are migrated to the capacity

tier, meeting service performance requirements. In addition, the TCO of the storage system is

minimized and the costs of users are reduced.

SmartTier has two migration triggering modes: manual and automatic. The manual triggering

mode has a higher priority than the automatic one. In manual triggering mode, data migration

can be triggered immediately when necessary. In automatic triggering mode, data migration is

automatically triggered based on a preset migration start time and duration. The start time and

duration of data migration are user-definable.




In addition, SmartTier supports three levels of data migration speeds: high, medium, and low.

The upper limits of the low-level, medium-level, and high-level data migration rates are 10

MB/s, 20 MB/s, and 100 MB/s respectively.


The data relocation module migrates data based on migration policies. In the

user-defined migration period, data is automatically migrated.

The data relocation module migrates data among various storage tiers based on migration

granularities and the data migration solution generated by the data placement analysis module. In this way, data is migrated based on activity levels and access sequences.

The data relocation module dynamically controls data migration based on the current load of a storage pool and the preset data migration speed.

The minimum unit for data migration is extent. Service data can be correctly accessed

during migration. Relocating an extent is to read data from the source extent and write

the data to the target extent. During data migration, read I/Os read data from the source

extent while write I/Os write data to both the source and target extents. After data

migration, the metadata of the source and target extents is modified. Then read and write I/Os access the target extent. The source extent is released.



Technical White Paper 10 SmartThin

10 SmartThin

The V3 converged storage systems support Huawei's self-developed SmartThin feature. This

feature is used to implement thin provisioning. SmartThin allows users to allocate desired

capacities to LUNs when creating LUNs. When LUNs are being used, storage capacities are

allocated on demand to improve storage resource utilization and meet the requirements of

growing services. SmartThin does not allocate all space out, but presents users a virtual

storage space larger than the physical storage space. In this way, users see larger storage space

than the actual storage space. When users begin to use storage space, SmartThin provides

only required space to users. If the storage space is insufficient, SmartThin expands the

capacity of the back-end storage unit. The whole expansion process is transparent to users and

causes no system downtime.

If the actual amount of data is larger than expected, LUN space can be adjusted dynamically.

Free space can be allocated to any LUN that needs space. In this way, storage space utilization

and effectiveness are improved. In addition, LUN space can be adjusted online without

affecting services.

SmartThin creates thin LUNs based on RAID 2.0+ virtual storage resource pools. Thin LUNs

and thick LUNs coexist in a same storage resource pool. Thin LUNs are logical units created

in a thin pool. They can be mapped and then accessed by hosts. The capacity of a thin LUN is

not its actual physical space, but only a virtual value. Only when the thin LUN starts to

process an I/O request, it applies for physical space from the storage resource pool based on

the COW policy.

SmartThin allows a host to detect a capacity larger than the actual capacity of a thin LUN.

The capacity detected by a host is the capacity that a user can allocate to the thin LUN,

namely the volume capacity (virtual space) displayed on the host after a thin LUN is created

and mapped to the host. The actual capacity of a thin LUN refers to the physical space

actually occupied by a thin LUN. SmartThin hides the actual capacity of the thin LUN from

the host and provides only the nominal capacity of the thin LUN.

In addition, SmartThin allows users to create a thin LUN whose capacity is larger than the

maximum available physical capacity of a storage resource pool. For example, if the

maximum physical capacity of a storage resource pool is 2 TB, SmartThin allows users to

create a thin LUN larger than 10 TB.

SmartThin uses the capacity-on-write and direct-on-time technologies to respond to read and

write requests from hosts to thin LUNs. Capacity-on-write is used to allocate space upon

writes, and direct-on-time is used to redirect data.

Capacity-on-write




When a thin LUN receives a write request from a host, the thin LUN uses direct-on-time

to determine whether the logical storage location of the request is allocated with an

actual storage location. If the actual storage location is not allocated, a space allocation

task is triggered with a minimum grain of 64 KB. Then data is written to the newly

allocated actual storage location.

Direct-on-time

Because capacity-on-write is used, the relationship between the actual storage location

and logical storage location of data is not calculated using the formulas, but is

determined by mappings based on capacity-on-write. Therefore, when a thin LUN is read

or written, the relationship between the actual storage location and logical storage

location must be updated based on the mapping table. A mapping table is used to record

mappings between actual storage locations and logical storage locations. A mapping

table is dynamically updated in the write process and is queried during the read process.

Therefore, direct-on-time is divided into read direct-on-time and write direct-on-time.

− Read direct-on-time: After a thin LUN receives a read request from a host, it queries

the mapping table. If the logical storage location of the read request is assigned an

actual storage location, the thin LUN redirects the logical storage location to the

actual storage location, reads data from the actual storage location, and returns the

read data to the host. If the logical storage location of the read request is not assigned

an actual storage location, the thin LUN sets data at the logical storage location to all

zeros and returns all zeros to the host.

− Write direct-on-time: After a thin LUN receives a write request from a host, it queries

the mapping table. If the logical storage location of the write request is assigned an

actual storage location, the thin LUN redirects the logical storage location to the

actual storage location, writes data to the actual storage location, and returns an

acknowledgement to the host indicating a successful data write. If the logical storage

location of the write request is not assigned an actual storage location, the thin LUN performs operations based on capacity-on-write.

SmartThin supports the online expansion of a single thin LUN and a single storage resource

pool. The two expansion methods do not affect services running on a host.

The expansion of a single thin LUN is to expand the nominal storage space of the thin

LUN. After the nominal storage space of a thin LUN is modified, SmartThin provides

the new nominal storage space of the thin LUN to the host. Therefore, the volume

capacity (virtual space) displayed on the host is the capacity after expansion. In the

expansion process, the original storage location is not adjusted. If new data needs to be

written to the newly added thin LUN storage space, the thin LUN applies for physical

space from the storage resource pool based on capacity-on-write.

The expansion of a storage resource pool is a capability provided by RAID 2.0+ storage

virtualization. Storage capacities are expanded without affecting services running on

hosts. In addition, SmartMotion balances data among all the disks including newly added

disks in the storage resource pool.

SmartThin provides two methods of space reclamation: standard SCSI command (unmap)

reclamation and all-zero data space reclamation. The working principles of these two methods

are described as follows:

Standard SCSI command reclamation: When a virtual machine is deleted, a host issues

the unmap command using the SCSI protocol. After receiving this command, SmartThin

uses direct-on-time to search for the actual storage location that corresponds to the

logical storage location to be released on a thin LUN, releases the actual storage location

on the thin LUN to a storage resource pool, and removes the mapping from the mapping

table. To use this space reclamation method, applications on hosts must be able to issue the unmap command. VMware, SF, and Windows 2012 support the unmap command.




All-zero data space reclamation: When receiving the write request from a host,

SmartThin determines whether data blocks contained in the write request are all zeros. If

the logical storage location that issues the all-zero data space is not allocated with an

actual storage location, SmartThin returns a message indicating a successful data write to

the host without space allocation. If the logical storage location that issues the all-zero

data space is allocated with an actual storage location, SmartThin releases the actual

storage location from the thin LUN to the storage resource pool, removes the mapping

from the mapping table, and returns a message indicating a successful data write to the host. This space reclamation method does not require any special commands from hosts.



Technical White Paper 11 SmartQoS

11 SmartQoS

The V3 converged storage systems support Huawei's self-developed SmartQoS feature. This

feature is used to ensure the QoS. SmartQoS intelligently schedules and allocates computing

resources, cache resources, concurrent resources, and disk resources of a storage system,

meeting the QoS requirements of services that have different priorities.

SmartQoS uses the following technologies to ensure the quality of data services:

I/O priority scheduling: Service response priorities are divided based on the importance

levels of different services. When allocating system resources, a storage system gives

priority to the resource allocation requests initiated by services that have the high priority.

If resources are in shortage, more resources are allocated to services that have the high

priority to maximize their QoS. Currently, three priorities are available: high, medium,

and low.

I/O traffic control: Based on a user-defined performance control goal (IOPS or

bandwidth), the traditional token bucket mechanism is used to control traffic. I/O traffic

control prevents specific services from generating excessive large traffic that affects

other services.

I/O performance assurance: Based on traffic suppression, a user is allowed to specify

the lowest performance goal (minimum IOPS/bandwidth or maximum latency) for a

service that has a high priority. If the minimum performance of the service cannot be

ensured, the storage system gradually increases the I/O latency of low-priority services,

thereby restricting the traffic of low-priority services and ensuring the lowest performance goal of high-priority services.

The I/O priority scheduling is implemented based on storage resource scheduling and

allocation. In different application scenarios, the performance of a storage system is

determined by the consumption of storage resources. Therefore, the system performance is

optimized as long as resources, especially bottleneck resources, are properly scheduled and

allocated. The I/O priority scheduling technique monitors the usage of computing resources,

cache resources, concurrent resources, and disk resources. If a resource bottleneck occurs,

resources are scheduled to meet the needs of high-priority services to the maximum. In this

way, the QoS of mission-critical services is ensured in different scenarios.

The I/O priority scheduling technique employed by SmartQoS schedules critical bottleneck

resources on I/O paths. Those resources include computing resources, cache resources,

concurrency resources, and disk resources. Scheduling policies are implemented based on

user-defined LUN priorities. The priority of a LUN is determined by the importance of

applications served by the LUN. There are three LUN priorities available: high, medium, and

low.




The I/O priority scheduling technique controls the allocation of front-end concurrency

resources, CPU resources, cache resources, and back-end disk resources to control the

response time of each schedule object.

Priority scheduling of front-end concurrency resources is implemented at the front end

of the storage system to control concurrent access requests from hosts. A storage

system's capability to process concurrent host access requests is limited. Therefore, when

the maximum number of concurrent host accesses allowed by a storage system is

reached, SmartQoS restricts the maximum number of concurrent accesses for each

priority based on the number of LUNs of each priority running under each controller.

The restriction principle is as follows: High-priority services and large-traffic services

are allocated a larger number of concurrent access resources.

Priority scheduling of computing resources is implemented by controlling the allocation

of CPU runtime resources. Based on the weight of each of high, medium, and low

priorities, SmartQoS allocates CPU runtime resources to services of each priority. When

CPU resources become a performance bottleneck, priority scheduling ensures that high-priority services are allocated more CPU runtime resources.

Priority scheduling of cache resources is implemented by controlling the allocation of

cache page resources. Based on the weight of each priority, SmartQoS first processes

page allocation requests initiated by high-priority services.

Priority scheduling of disk resources is implemented by controlling the I/O delivery

sequence. Based on the priorities of I/Os, SmartQoS enables high-priority I/Os to access

disks first. If most I/Os are queuing on the disk side, priority scheduling of disk

resources reduces the queuing time of high-priority I/Os. In this way, the overall latency

of high-priority I/Os is reduced.

The priority scheduling technique employed by SmartQoS is implemented based on LUN

priorities. Each LUN has a priority property, which is configured by a user and saved in a

database. When a host (SCSI target) sends an I/O request to a disk array, the disk array gives a

priority to the I/O request based on the priority of the LUN that will process the I/O request.

Then the I/O carries the priority throughout its processing procedure.

The I/O traffic control technique of SmartQoS:

Restricts the performance of some applications in the system by limiting the total IOPS

or bandwidth of one or multiple LUNs in the storage system. This technology prevents

those applications from generating high burst traffic that may affect the performance of other services in the system.

Limits data processing resources available for data services on specific LUNs. The

objects of traffic control consist of the I/O class (read, write, or read and write) and

traffic class (IOPS or bandwidth). Based on the two classes, a 2-tuple (I/O class and

traffic class) is obtained for traffic control specific to a certain LUN.

Controls traffic based on the I/O class and the obtained 2-tuple. Each I/O class

corresponds to one traffic control group. Each traffic control group contains a certain

number of LUNs and LUN groups whose maximum traffic is restricted. The I/O

class-based traffic control function is implemented based on the I/O class queue management, token allocation, and dequeue control.

The I/O latency control technique of SmartQoS ensures the minimum performance

requirements of some critical services by restricting low-priority services. Users can set

minimum performance requirements for high-priority services. If those requirements cannot

be met, the storage system restricts low- and medium-priority services in sequence to ensure

the minimum performance set for the high-priority services.

SmartQoS restricts the performance of low- and medium-priority services by gradually

increasing their latency. To prevent performance instability, SmartQoS does not prolong the




latency after the latency reaches the upper limit. If the actual lowest service performance

becomes 1.2 times of the preset lowest performance indicator, the storage system gradually

cancels the increased latency of low- and medium-priority services.



Technical White Paper 12 SmartPartition

12 SmartPartition

The V3 converged storage systems support Huawei's self-developed SmartPartition feature.

This feature is used to optimize cache partitioning. The core idea of SmartPartition is to

ensure the performance of mission-critical applications by partitioning core system resources.

An administrator can allocate a cache partition of a specific size to an application. The storage

system ensures that the application uses the allocated cache resources exclusively. Based on

the actual service condition, the storage system dynamically adjusts the front- and back-end

concurrent accesses to different cache partitions, ensuring the application performance of each

partition. SmartPartition can be used with other QoS technologies (such as SmartQoS) to

achieve better QoS effects.

Caches are classified into read caches and write caches. The read cache pre-fetches and

retains data to improve the hit ratio of read I/Os. The write cache improves the disk access

performance by means of combination, hitting, and sequencing. Different services need read

and write caches of different sizes. SmartPartition allows users to specify read and write cache

sizes for a partition, meeting cache requirements of different services.

The read cache configuration and the write cache configuration affect the I/O procedure

differently. The impact on the write I/Os shows up in the phase of cache resource allocation.

In this phase, the host concurrency and write cache size of a partition are determined. The

reason for determining the two items in this phase is that it is the initial phase of a write

procedure and the cache of the storage system is actually not occupied in this phase.

The impact on read I/Os involves two aspects. The first aspect is similar to the write I/O

scenario. Specifically, the storage system determines whether the host concurrency meets the

requirement. If not, the storage system returns the I/Os. The read cache is intended to control

the size of the cache occupied by read data. The size of a read cache is controlled by the read

cache knockout procedure. Therefore, the second aspect of the impact shows up in the read

cache knockout procedure. If the read cache size of the partition does not reach the threshold,

read cache resources are knocked out extremely slowly. Otherwise, read cache resources are

knocked out quickly to ensure that the read cache size is below the threshold.

Compared with host applications, the processing resources of a storage system is limited.

Therefore, a storage system must restrict the total host concurrency amount. For each partition,

the concurrency is also restricted to ensure the QoS.



Technical White Paper 12 SmartPartition

Regarding SmartPartition, the host concurrency of a partition is not fixed but calculated based

on the priority weighted algorithm with the following factors taken into account:

Number of active LUNs in the partition in the last statistics period

Priorities of active LUNs in the partition in the last statistics period

Number of I/Os completed by each LUN in the last statistics period

Number of I/Os returned to hosts because the partition concurrency reaches the threshold

in the last statistics period

Weighting the preceding factors not only fully uses the host concurrency capability but also

ensures the QoS of a partition.

After one statistics period elapses, the concurrency capability of a partition may need to be

adjusted based on the latest statistical result. The SmartPartition logic adjusts the concurrency

capability based on a specific step to ensure a smooth adjustment, minimizing host

performance fluctuation.

Similar to host concurrency control, back-end concurrency control is also intended to fully

use system resources while ensuring the QoS of a partition. The back-end concurrency is

calculated based on the priority weighted algorithm with the following factors taken into

account:

Amount of dirty data on high-priority LUNs in a partition in the last statistics period

Disk flushing latency of LUNs in a partition in the last statistics period

Actual disk flushing concurrency of LUNs in a partition in the last statistics period

The adjustment period and approach are similar to those of host concurrency control.



Technical White Paper 13 DeviceManager

13 DeviceManager

The HUAWEI OceanStor DeviceManager (DeviceManager) is the web-based software that allows users to

manage the V3 converged storage systems support according to the user level of authorization (administrator,

operator, auditor, customized operator).

It has the following characteristics:

The software is built in storage systems. Users can log in to its management interface using a web browser.

Graphical navigation makes operation entries clearly and vividly displayed.

Administrators can quickly get started with the software and manage the users.

Centralized configuration entries reduce the procedures and page switching times of storage management

tasks.

Initial configuration greatly simplifies the process from storage system initialization to storage resource

allocation.

Various means of event notification allow administrators to initiate active storage management.

Manage history events and operation logs and the rules for the logs, change the way the storage stores the

compressed packages of old logs and operation logs of nodes. The basic retention period is: 90 days (while that of

operation logs is 365 days).

Classified operations reduce the possibility of misoperations and enhance users' confidence.

Performance statistics help administrators find and smash performance bottlenecks.



Technical White Paper 14 Summary

14 Summary

The V3 converged storage systems are brand-new converged storage systems that employ a

cloud-oriented architecture. Built based on block-level virtualization and SAN and NAS

convergence, the storage systems support online deduplication and compression and

heterogeneous virtualization. Thanks to the converged architecture, the V3 converged storage

systems boast rich advanced features, such as scale-out, SmartDedupe, SmartCompression,

and SmartVirtualization. In addition, SmartPartition and SmartCache accelerate and improve

the performance of file system sharing and block-based access, and SmartDedupe and

SmartThin improve the storage efficiency. Based on the converged architecture, the V3

storage systems apply to scenarios involving virtualization, heterogeneous storage, file servers,

and databases. Huawei is dedicated to providing high-quality storage products and

user-friendly services for customers. Guiding by this concept, the V3 converged storage

systems fully meet customers' requirements for high performance, functions, and efficiency,

and maximize customers' benefits.



Technical White Paper 15 Acronyms and Abbreviations

15 Acronyms and Abbreviations

Table 15-1 Acronyms and abbreviations

Acronym and Abbreviation Full Spelling

BBU Backup Battery Unit

BP Block Point

DIF Data Integrity Field

eDevLUN External Device LUN

HDD Hard Disk

IOPS Input and Output Per Second

KV_DB KeyValue-DataBase

LUN Logical Unit Number

NL-SAS Nearline Serial Attached SCSI

OLAP On Line Analysis Process

OLTP On Line Transaction Process

QoS Quality of Service

RAID Redundant Array of Independent Disks

SAS Serial Attached SCSI

SCSI Small Computer System Interface

SSD Solid State Disk

TCO Total Cost Ownership

Thick LUN Thick LUN

Thin LUN Thin LUN

WAFL Write Anywhere File Layout

WWN World Wide Number

Documents

HUAWEI OceanStor 5300&5500&5600&5800 V3 Converged Storage … · · 2015-01-2815 Acronyms and Abbreviations..... 38. HUAWEI OceanStor 5300&5500&5600&5800 V3 Converged Storage Systems